Donald Trump again attacked Elizabeth Warren on Thursday, calling her "Pocahontas" during a press conference in North Dakota and prompting pushback from a person identified as a reporter.

"That's very offensive," the person shouted.

"Oh, I'm sorry about that," Trump said.

"Pocahontas? Is that what you said? Elizabeth Warren?" he said.

He said he hits back at the Massachusetts senator because "she tweets a lot about" him.

"She is a senator that's highly overrated," he said. "She's passed very little legislation. Frankly, many of the Democrats can't stand her. Just ask Hillary Clinton how she likes her."

Trump then rekindled a line of attack aimed at her heritage. Scott Brown, a Trump supporter who was Warren's opponent during her 2012 Senate bid, accused her at the time of using her Native American ancestry to her advantage after reports surfaced that she listed herself as a minority in a years-old directory of law professors.

"'Well, I have high cheek bone. You see I have high cheek bones, so I'm a Native American,'" Trump said mockingly on Thursday. "I don't know if you would call it a fraud or not but she was able to get into various schools because she applied as a Native American. I think she's as Native American as I am, OK? That I will tell you."

"She's a woman that's been very ineffective, other than that she's got a big mouth," he continued.

On Tuesday, Warren slammed Trump for his past expression of openness for a downturn in the real-estate market ahead of the 2008 housing crash.

"To root for people to lose their pensions, to root for two little girls in Clark County, Nevada, to end up living out of a van — what kind of a man does that?" Warren said. "I'll tell you exactly what kind of a man does that. It's a man who cares only about himself. A small, insecure money-grubber who doesn't care who gets hurt as long as he makes a profit."